The present invention relates to an oil supply structure for an engine cylinder head, and more particularly, to a technique for supplying oil for activation of a variable valve timing apparatus and lubrication of a cylinder head.
In general, a cylinder head of an engine is formed with a cam shaft that continuously rotates for opening or closing valves while the engine is in operation, such that lubricating oil must be continuously supplied at all times. Further, some variable valve timing apparatus used for advancing or retarding the opening/closing time period of valves utilize oil pressure as an operational power source. Accordingly, an engine having a variable valve timing apparatus, which uses oil pressure as an operational power source, should be supplied with both a lubricating oil for a cylinder head and an oil for the variable valve timing apparatus.
The present invention provides an oil supply structure for an engine cylinder head configured to smoothly supply lubricating oil for the cylinder head and operational oil for the variable valve timing apparatus which uses oil pressure as the operational power source. The present invention also is configured to allow components of a variable valve timing apparatus to be easily mounted and maintained.
In a preferred embodiment of the present invention, the oil supply structure comprises an oil chamber so formed as to receive the oil from a main oil gallery of a cylinder block at a lower portion of a cylinder head abutted on an upper portion of the cylinder block. A cam shaft journal oil passage branches from the oil chamber for lubricating a cam shaft journal part. And an oil supply passage branches from the oil chamber for operating a variable valve timing apparatus.